California is four years into a historic drought, and water for human use is vying with the water needs of wildlife, such as threatened salmon.

In parts of northern California, an explosive and unregulated increase in marijuana cultivation is contributing to the problem. Now, a study says the impact of pot grows on fish-bearing streams is threatening their survival.

Researchers monitoring water levels in streams in Humboldt and Mendocino Counties last summer say the water impacts of cannabis grow operations are dramatic.

In Les Parks’ perfect world, the Tulalip Tribes would not only legalize marijuana but fund research into its medical benefits.

“I see Tulalip leading the country and being on this frontier for what this plant can do for mankind, basically,” said Parks, the Tulalips’ vice chairman and a longtime supporter of legalization, speaking from the tribe’s gleaming new government building, with sweeping views over Puget Sound.

Ross Reynolds speaks with North Bonneville Mayor Don Stevens about their city's pot store. It will become the first government-owned pot store in the nation, possibly the world, when it opens on Saturday.

Alaska's voter initiative making marijuana legal takes effect Tuesday, placing Alaska alongside Colorado and Washington as the three U.S. states where recreational marijuana is legal. The new law means people over age 21 can consume small amounts of pot — if they can find it. It's still illegal to sell marijuana.

"You can still give people marijuana, but you can't buy it — or even barter for it," Alaska Public Media's Alexandra Gutierrez reports. "So, it's a pretty legally awkward spot. That probably won't stop people from acquiring it, though."

Like many schools across Colorado, Arapahoe Ridge High School in Boulder has seen an increase in overall drug incidents since recreational marijuana became legal.

While public schools aren't required to report marijuana incidents separately from other drugs such as cocaine, evidence compiled by Rocky Mountain PBS I-News suggests more students are using marijuana.

In 2012 Washington voters’ approved Initiative 502. Passage of the measure set in place a licensing and regulation scheme and rescinded state laws criminalizing recreational marijuana use and possession. It legalized the production, sale and taxation of small amounts of marijuana-related products for adults 21 and over.